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The step-recovery-diode-based impulse generator is a classical picosecond-level impulse-formation technique, whose strong harmonic nonlinearity under sinusoidal stimulus is widely utilized as the phase reference of the nonlinear vector network analyzer (VNA) (NVNA) and large-signal network analyzer for wideband measurements. This paper further exploits its intermodulation nonlinearity under multitone stimulus and proposes a new approach, rather than the traditional “harmonic” way, of the NVNA phase reference for future polyharmonic intermodulation measurements. Experimental results show that this method can provide plentiful intermodulation components around each harmonic available and is stable for NVNA use, with the advantages of flexible local frequency-resolution setup from tens of megahertz to less than hundreds of hertz. [ABSTRACT FROM PUBLISHER]

This paper studies the systematic uncertainties of nonlinear vector network analyzer (NVNA) measurements and presents a covariance-matrix-based method to analyze the uncertainty propagation from calibration standards and hardware to error model terms and effective measurements. Analytic deductions of the Jacobians for frequency-domain quantities are proposed, dealing with the complex NVNA measurements and calibration functions. An NVNA two-port-calibration uncertainty is put forward as a new kind of systematic uncertainty consideration for this vector-correction-based instrument. Experiments on our prototype NVNA show the necessity of using covariance-matrix-based uncertainty analysis, particularly for polyharmonic measurements, and reveal some features of NVNA uncertainty analysis due to the calibration techniques. [ABSTRACT FROM PUBLISHER]